Alternative Building Materials

Step 1: Standard Brick Size.
As per the IS code, the standard size of a brick is 210 mm in length, 110 mm in width, and 110 mm in height.
Step 2: Analysis of the Options.
- (A) 220 x 120 x 120: This is not the standard size.
- (B) 190 x 90 x 90: This size does not conform to the IS code for standard bricks.
- (C) 200 x 100 x 50: This is not a standard brick size.
- (D) 210 x 110 x 110: This matches the standard size as per IS code.

Step 3: Conclusion.
The correct standard size of a brick is 210 x 110 x 110 mm, making (D) the correct answer.

Final Answer: